;逻辑或
(define (logical-or x y)
    (if (and (= x 0) (= y 0))
        0
        1))

;或门
(define (or-gate a1 a2 output)
    (define (or-action-procedure)
        (let ((new-value
                (logical-or (get-signal a1) (get-signal a2))))
            (after-delay or-gate-delay
                         (lambda ()
                            (set-signal! output new-value)))))
    (add-action! a1 or-action-procedure)
    (add-action! a2 or-action-procedure)
    'ok)